DESCRIPTION: Much of the ability to move depends upon networks of neurons in the spinal cord and hindbrain. Recent evidence indicates that there is a relatively simple structural and functional organization in spinal cord that may extend into the hindbrain. This proposal explores whether there is a basic template to the organization of neurons and their wiring in hindbrain that is established during development and that underlies the control of movement. Such a template would provide a conceptual organization that would enhance in a major way the understanding of the organization of a part of the brain that is critical for normal movement and whose proper function is disrupted in disease and after spinal injury. The proposed work stems from the discovery that neurons in hindbrain are clustered into stripes based on neurotransmitter. The proposal takes advantage of the ability to see into the brain and spinal cord of intact larval zebrafish to explore 1) whether the stripes correspond to transcription factors and how the stripes develop, 2) whether neurons within a stripe are similar to one another and project in a regular way to neurons in other stripes, 3) whether the electrical properties of neurons within a stripe vary systematically with their position and age in a way that might lead to their orderly activation during normal movements and 4) whether the position of a neuron in a stripe reflects the speed of the movement in which it is activated. The proposed work will reveal basic principles that link development with the later structure and function of neurons in the hindbrain. These will inform us about brain organization in vertebrates, including humans, and should help us to interpret and eventually treat movement disorders.